A fresh look at interferon-alpha signaling and treatment outcomes in chronic hepatitis C

Cytokines and HCV-related autoimmune disorders

Cytokines are intercellular mediators involved in viral control and liver damage being induced by infection with hepatitis C virus (HCV). The complex cytokine network operating during initial infection allows a coordinated, effective development of both innate and adaptive immune responses. However, HCV interferes with cytokines at various levels and escapes immune response by inducing a T-helper (Th)2/T cytotoxic 2 cytokine profile. Inability to control infection leads to the recruitment of inflammatory infiltrates into the liver parenchyma by interferon (IFN)-γ-inducible CXC chemokine ligand (CXCL)9, -10, and -11 chemokines, which results in sustained liver damage and eventually in liver cirrhosis. The most important systemic HCV-related extrahepatic diseases-mixed cryoglobulinemia, lymphoproliferative disorders, thyroid autoimmune disorders, and type 2 diabetes-are associated with a complex dysregulation of the cytokine/chemokine network, involving proinflammatory and Th1 chemokines. The therapeutical administration of cytokines such as IFN-α may result in viral clearance during persistent infection and revert this process. Theoretically agents that selectively neutralize CXCL10 could increase patient responsiveness to traditional IFN-based HCV therapy. Several studies have reported IL-28B polymorphisms and circulating CXCL10 may be a prognostic markers for HCV treatment efficacy in HCV genotype 1 infection.

Twenty-five years of type I interferon-based treatment: a critical analysis of its therapeutic use

The clinical exploitation of type I interferon (IFN) as an antiviral and antineoplastic agent is based on the properties originally attributed to this cytokine family, with schedules reflecting only their antiviral and antiproliferative activities. Nevertheless, type I IFN has emerged as a central activator of the innate immunity. As current schedules of treatment for chronic hepatitis C and for hematological and solid tumors, based on the continuous administration of recombinant type I IFN or pegylated formulations, disregard viral resistance, host genetic variants predicting treatment outcome and mechanisms of refractoriness, new administration schedules, the combination of type I IFN with new drugs and the increased monitoring of patients' susceptibility to type I IFN are expected to provide a new life to this valuable cytokine.

Serum interferon-related microRNAs as biomarkers to predict the response to interferon therapy in chronic hepatitis C genotype 4

Background

Hepatitis C virus genotype 4 (HCV-4) infection is common in the Middle East and Africa, with an extraordinarily high prevalence in Egypt. MicroRNAs (miRNAs) play an important role in various diseases, including HCV infection. The aim of the present study was to assess serum miR-122, miR-221 and miR-21 expression profiles in HCV-4 patients prior to treatment with HCV-4 combination therapy (pegylated alpha interferon and ribavirin) and to determine whether the miRNAs were associated with the drug response.

Methods

RNA was extracted from pretreatment serum samples, and miR-122, miR-221 and miR-21 levels were measured by quantitative PCR. The results were compared among patients with sustained virological responses (SVR) and non-responders (NR).

Results

The expression levels of miR-21 and miR-122 were significantly different between the SVR and NR groups. Receiver operator characteristic (ROC) analysis revealed that the sensitivity, specificity and positive predictive values of miR-21 were 82.2%, 77.3% and 88.1%, respectively, with a cut-off value of 1.7. The sensitivity, specificity and positive predictive values of miR-122 were 68.9%, 59.1% and 77.5%, respectively, with a cut-off value of 3.5.

Conclusion and Significance

miR-21 and miR-122 might be useful predictors for SVR in HCV-4 patients prior to the administration of combination therapy. A higher predictive response power was obtained for miR-21 than for miR-122. These results should reduce ineffective treatments.

Serum interferon-related microRNAs as biomarkers to predict the response to interferon therapy in chronic hepatitis C genotype 4

MicroRNAs are messengers during interferon-virus interplay and are involved in antiviral immunity, however, little is known about interferon-related microRNAs regarding their detection in serum and their potential use as non-invasive diagnostic and prognostic biomarkers in chronic hepatitis C (CHC). To elucidate some of the molecular aspects underlying failure of pegylated interferon-α/ribavirin therapy, we investigated pretreatment expression profiles of seven selected interferon-related microRNAs (miR-146a, miR-34a, miR-130a, miR-19a, miR-192, miR-195, and miR-296) by quantitative RT-PCR custom array technology in serum of Egyptian CHC genotype 4 patients and whether their pretreatment levels would predict patient response to the combination therapy. One hundred and six CHC patients and forty matched healthy controls were included. Patients were divided into sustained virological response (SVR) and non-responder (NR) groups. Serum miR-34a, miR-130a, miR-19a, miR-192, miR-195, and miR-296 were upregulated, whereas serum miR-146a was downregulated in CHC compared to controls. Significant correlations were found between expression levels of studied microRNAs and also with clinical data. Pretreatment levels of miR-34a, miR-130a, and miR-195 were significantly higher, whereas miR-192 and miR-296 levels were significantly lower in SVR than NR patients. miR-19a and miR-146a levels were not significantly different between the two groups. miR-34a was superior to differentiate CHC from controls, whereas miR-296 was superior to discriminate SVR from NR patients by receiver operating characteristic analysis. Multivariate logistic analysis revealed miR-34a and miR-195 as independent predictors for SVR and miR-192 as an independent variable for non-response. In conclusion, pretreatment expression profiles of five interferon-related microRNAs are associated with treatment outcome in CHC. Of these, miR-34a, miR-195, and miR-192 could predict treatment response. The profiling results could be used as novel non-invasive diagnostic and prognostic pharmacogenetic biomarkers for treatment personalization in CHC and could help to identify new microRNA-based antivirals.

Vitamin D status and serum ferritin concentration in chronic hepatitis C virus type 1 infection

The circulating 25-hydroxylated form of vitamin D(3), 25(OH)D, and serum ferritin concentrations have been described to be associated with disease progression in chronic hepatitis C. Both parameters also have been assessed with regard to treatment outcome, however, with divergent results. This study examined both the pre- and posttreatment serum concentrations of 25(OH)D and ferritin in 191 patients infected chronically with hepatitis C virus (HCV) type 1 with regard to liver inflammatory activity (grading), disease progression in terms of fibrosis (staging) and an antiviral treatment outcome. Mean pretreatment serum 25(OH)D and ferritin concentrations were 18 ± 10 ng/ml and 280 ± 225 µg/L, respectively. Multivariate analysis revealed lower pretreatment serum 25(OH)D and higher ferritin concentrations to be significantly related to both severity of inflammatory activity and of fibrotic alterations. Pretreatment serum ferritin concentration, furthermore, unlike 25(OH)D concentration, was found to be associated with a sustained virological response by uni- and multivariate analyses. A sustained virological response was featured by a significant increase in serum 25(OH)D levels (18 ± 10 ng/ml vs. 22 ± 11 ng/ml; P < 0.01), a reduction of serum ferritin concentration (191 ± 156 µg/L vs. 103 ± 63 µg/L; P < 0.001) and a normalization of serum alanine aminotransferase (ALT) and γ-glutamyl-transferase (γ-GT) activities. Taken together, decreased 25(OH)D and increased ferritin serum levels indicate the severity of hepatic inflammation and fibrosis in patients infected chronically with HCV type 1. Elevated ferritin, furthermore, was found to be an independent predictor for standard IFN-based therapy responsiveness.

Aptamers: novel molecules as diagnostic markers in bacterial and viral infections?

Worldwide the entire human population is at risk of infectious diseases of which a high degree is caused by pathogenic protozoans, worms, bacteria, and virus infections. Moreover the current medications against pathogenic agents are losing their efficacy due to increasing and even further spreading drug resistance. Therefore, there is an urgent need to discover novel diagnostic as well as therapeutic tools against infectious agents. In view of that, the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) represents a powerful technology to target selectively pathogenic factors as well as entire bacteria or viruses. SELEX uses a large combinatorial oligonucleic acid library (DNA or RNA) which is processed a by high-flux in vitro screen of iterative cycles. The selected ligands, termed aptamers, are characterized by high specificity and affinity to their target molecule, which are already exploited in diagnostic and therapeutic applications. In this minireview we will discuss the current status of the SELEX technique applied on bacterial and viral pathogens.

IL28B genotype and the expression of ISGs in normal liver

BACKGROUND & AIMS

Both polymorphisms in the IL28B gene locus and ISG expression levels are associated with the outcome of hepatitis C virus (HCV) infection. The two are also interrelated, although the mechanism is unknown. Favourable CC genotype at rs12979860 expresses lower baseline ISG levels and responds better to treatment than unfavourable CT and TT genotypes. Little is known about this relationship in normal, uninfected liver. This study sought to explore this relationship.

METHODS

Normal human liver specimens (64) and HCV positive human liver specimens (95) were genotyped for IL28B rs12979860 C > T. mRNA levels of ISGs and other relevant genes were studied by qPCR.

RESULTS

Most studied ISGs had significantly different expression by IL28B genotype in normal liver. CC genotype expressed the highest levels, CT intermediate and TT the lowest. This is opposite to the pattern seen in HCV patients. Principal component analysis of IL28B genotype and ISG expression further revealed a distinct set of genes correlated with the C allele (ISG15, HTATIP2, LGALS3BP, IRF2 and BCL2) and T allele (IFNα, β, γ, λ3 and CD80).

CONCLUSION

A subset of ISGs was found to be differentially expressed in normal liver by IL28B genotype. This suggests a relationship between IL28B genotype and gene expression before HCV infection.

Cytokines and HCV-related disorders

Cytokines are intercellular mediators involved in viral control and liver damage being induced by infection with hepatitis C virus (HCV). The complex cytokine network operating during initial infection allows a coordinated, effective development of both innate and adaptive immune responses. However, HCV interferes with cytokines at various levels and escapes immune response by inducing a T-helper (Th)2/T cytotoxic 2 cytokine profile. Inability to control infection leads to the recruitment of inflammatory infiltrates into the liver parenchyma by interferon (IFN)-gamma-inducible CXC chemokine ligand (CXCL)-9, -10, and -11 chemokines, which results in sustained liver damage and eventually in liver cirrhosis. The most important systemic HCV-related extrahepatic diseases--mixed cryoglobulinemia, lymphoproliferative disorders, thyroid autoimmune disorders, and type 2 diabetes--are associated with a complex dysregulation of the cytokine/chemokine network, involving proinflammatory and Th1 chemokines. The therapeutical administration of cytokines such as IFN-alpha may result in viral clearance during persistent infection and reverts this process.

Vitamin D deficiency and a CYP27B1-1260 promoter polymorphism are associated with chronic hepatitis C and poor response to interferon-alfa based therapy

BACKGROUND & AIMS

Vitamin D is an important immune modulator and preliminary data indicated an association between vitamin D deficiency and sustained virologic response (SVR) rates in hepatitis C virus (HCV) genotype 1 patients. We, therefore, performed a comprehensive analysis on the impact of vitamin D serum levels and of genetic polymorphisms with functional relevance within the vitamin D cascade on chronic hepatitis C and its treatment.

METHODS

Vitamin D serum levels, genetic polymorphisms within the vitamin D receptor and 1α-hydroxylase were determined in a cohort of 468 HCV genotype 1, 2, and 3 infected patients who were treated with interferon-alfa based regimens.

RESULTS

Chronic hepatitis C was associated with a high incidence of severe vitamin D deficiency compared to controls (25(OH)D(3)<10 ng/ml in 25% versus 12%, p<0.00001). 25(OH)D(3) deficiency correlated with SVR in HCV genotype 2 and 3 patients (50% and 81% SVR for patients with and without severe vitamin D deficiency, respectively, p<0.0001). In addition, the CYP27B1-1260 promoter polymorphism rs10877012 had substantial impact on 1,25-dihydroxyvitamin D serum levels (72, 61, and 60 pmol/ml for rs10877012 AA, AC, and CC, respectively, p=0.04) and on SVR rates in HCV genotype 1, 2, and 3 infected patients (77% and 65% versus 42% for rs10877012 AA, AC, and CC, respectively, p=0.02).

CONCLUSIONS

Chronic hepatitis C virus infection is associated with vitamin D deficiency. Reduced 25-hydroxyvitamin D levels and CYP27B1-1260 promoter polymorphism leading to reduced 1,25-dihydroxyvitamin D levels are associated with failure to achieve SVR in HCV genotype 1, 2, and 3 infected patients.

Differential expression of interferon-induced microRNAs in patients with chronic hepatitis C virus infection treated with pegylated interferon alpha

There have been reports of in-vitro interferon (IFN)-mediated antiviral activity against the hepatitis C virus (HCV) through microRNAs (miRNAs). The main aim of this study was to evaluate the expression of several miRNAs (miR-1, miR-30, miR-128, miR-196, miR-296) in peripheral blood mononuclear cells (PBMCs) from healthy individuals after in vitro IFN-treatment and in PBMCs from patients with chronic hepatitis C (CHC) before and 12 hours after the first injection of pegylated IFN alpha. We demonstrated that expression of these miRNAs could be recorded in PBMCs collected from healthy individuals before and after in-vitro IFN alpha treatment. Our analysis revealed that the levels of expression of all miRNAs investigated in patients with CHC were different to those in healthy individuals. When levels of the miRNAs were measured 12 hours after the first IFN injection, increases in expression levels of IFN-induced miRNAs were observed in 25-50% of patients, depending on the type of miRNA examined. No correlations were observed between HCV viral load, alanine aminotransferase status and expression of miRNA. Together these findings suggest that: (i) IFN alpha in-vitro treatment of PBMCs leads to a transcriptional induction of all miRNAs investigated; (ii) miRNAs can be induced differentially by IFN treatment in patients with HCV. Given the importance of miRNAs in defending the host against virus infections, it is possible that IFN-induced miRNAs may represent an important determinant of the clinical outcome of IFN therapy in HCV infection.

CS-SELEX generates high-affinity ssDNA aptamers as molecular probes for hepatitis C virus envelope glycoprotein E2

Currently, the development of effective diagnostic reagents as well as treatments against Hepatitis C virus (HCV) remains a high priority. In this study, we have described the development of an alive cell surface -Systematic Evolution of Ligands by Exponential Enrichment (CS-SELEX) technique and screened the functional ssDNA aptamers that specifically bound to HCV envelope surface glycoprotein E2. Through 13 rounds of selection, the CS-SELEX generated high-affinity ssDNA aptamers, and the selected ssDNA aptamer ZE2 demonstrated the highest specificity and affinity to E2-positive cells. HCV particles could be specifically captured and diagnosed using the aptamer ZE2. A good correlation was observed in HCV patients between HCV E2 antigen-aptamer assay and assays for HCV RNA quantities or HCV antibody detection. Moreover, the selected aptamers, especially ZE2, could competitively inhibit E2 protein binding to CD81, an important HCV receptor, and significantly block HCV cell culture (HCVcc) infection of human hepatocytes (Huh7.5.1) in vitro. Our data demonstrate that the newly selected ssDNA aptamers, especially aptamer ZE2, hold great promise for developing new molecular probes, as an early diagnostic reagent for HCV surface antigen, or a therapeutic drug specifically for HCV.